Means for controlling fluid flow



Jan. 9, 1934. H. J. MASTENBROOK MEANS FOR CONTROLLING FLUID FLOW Filed Dec. 6, 1928 nial 22 v Patented Jan. 9, 1934 UNITED STATES PATENT OFFICE MEANS FOR CONTROLLING FLUID FLOW Application December 6, 1928. Serial No. 324,187

26 Claims.

This invention relates to the control of flow of fluid and more particularly to the control of fluid pressure drop through an orifice or valve. I have illustrated an embodiment of my invention in a 'boiler feed water system wherein I desire to control the fluid pressure drop across a boiler feed water valve.

I am familiar with the construction disclosed in the Andrews Patent No. 1,396,239, wherein it is intended to maintain a constant drop across the feed water valve. I am also familiar with the construction illustrated in the application of Joseph M. Barrett, Serial No. 143,326, filed October 22nd, 1926, and patented March 22, 1932, No.

1,850,651, wherein the pressure drop across the feed water valve is varied by changing the compression in a spring of a differential valve, which measures the pressure drop across the feed water valve. I am also familiar with the differential .valve illustrated in the Barrett application, Serial No. 27,735, filed May 4, 1925, and patented October 7, 1930, No. 1,777,633, wherein manually operated needle valves are arranged to control diiferent connections to one of the fluid pressure chambers of the diflerential valve.

It is among the objects of my invention tocontrol the fluid pressure drop across a given valve or orifice such as a boiler feed water valve. A more specific object is to provide a valve actuable in response to the differential between certain fluid pressures and having means for automatically connecting various sources of pressure thereto to change the value of the differential. A further object is to arrange a control for the fluid pressiue drop across a feed water valve by means of the valve having a diaphragm chamber connected to a point between the feed water valve and the boiler and to interpose in this connection a pilot valve responsive to thermal conditions in 4,0 the boiler for closing this connection and opening another connection to a source of higher pressure to increase the drop across the feed water valve and to increase the boiler feed under given boiler conditions. A still further object is to arrange a three-way pilot valve to control the connections with at least one chamber of the differential valve and to connect this pilot valve with an agency responsive to changes in boiler conditions so that alternative or joint sources of pressure may be connected with the said chamber of the difierential valve.

In the following detailed description, as well as the claims, I may from time to time use the expression thermal conditions and/or boiler conditions with the intention of referrn'g broadly to one or more of several boiler conditions which I wish to include within this term. For example, boiler pressure is obviously a thermal as well as a boiler condition, since of course the steam pressure varies with the heat content of the boiler water as well as the steam. I regard boiler load as a thermal as well as a boiler condition, inasmuch as the rate of input of heat to the liquid is a necessary incident to the maintenance of output of boiler load. Insofar as the boiler feed is controlled by water level, a decrease in boiler water level is an incident to an increase in load and ipso facto a thermal condition as well as a boiler condition when viewed in this regard.

Other objects will appear from the following description of a preferred form of my invention, reference being had to the accompanying drawing. The essential characteristics are summarized in the claims The drawing represents an illustrative installation showing at least parts of the valves in crosssection.

In the drawing, I illustrate my invention as installed in the feed water line of a boiler wherein I desire to control the fluid pressure drop across the boiler feed Water valve. Thus I show the feed water line 1 leading to a boiler drum D in which it is desired to maintain a water level substantially along the line L. A steam outlet is indicated at 2. In the feed water line I employ a feed water valve 3 having an adjustable spring 4 urging the closure member toward closed position and having a diaphragm, not shown, but enclosed in a chamber 5 in which pressures are established to open the valve.

A conduit 6 leads from the chamber 5 to a fluid pressure generator 7 mounted on a conduit 8 which communicates with the steam and water spaces of the boiler drum. This installation may be similar in nature to that disclosed in the Copley Patent No. 1,193,125, wherein the generator comprises essentially a closed chamber surrounding the conduit 8 and containing an expansible fluid, such as water, which is volitalized as the level of water in the conduit 8 falls. The degree of pressure generated and established in the chamber 5 varies as the water level changes, thereby causing the valve 3 to open in response to a fall in water level.

To control the fluid pressure drop across the valve 3, I employ a valve 10 which is actuated in response to the difference in pressures established on opposite sides of its diaphragm 11. The valve 10 has a balanced closure member 12 to which is secured the stem 13, which in turn 23, the chamber 22 and the conduit 21.

is fixed to a diaphragm 11. The stem 13 lies within a chamber 14 which communicates with the outlet or low pressure side 15 of the valve 10. Thus the pressure in the line between the valves 10 and 3 is imposed upon the lower side of the diaphragm 11. Associated with the valve stem 13 is a spring 16 which exerts a downward pressure on the valve stem and which may be adjustably compressed through a screw 17 having an accessible head 18. The valve 10 is shown with the stem 13 extending upwardly for convenience of illustration. In practice the valve is inverted, with the stem extending downwardly so that cold water is trapped in contact with the diaphragm 11.

As illustrated in the above mentioned patent and application, the upper side of the diaphragm 11 closes a chamber 20 similar to the chamber 5. When this chamber is connected to communicate with the boiler or with the feed water line between the feed water valve and the boiler, then the pressure drop across the feed water valve equals the compression of the spring 16, because the sum of the pressure in the chamber 20 plus the pressure exerted by the spring 16 balances the pressure in the chambers 14 or 15. The spring may be compressed to give an ideal feed for a given condition of boiler load but conditions may continually be changing so that it is desirable from time to time to have greater or less pressure drops across the feed water valve. This I propose to do in the novel manner of bringing connections to the chamber 20 not only from the boiler but also from a source of higher pressure, as for instance the feed water pump and arrange a three way valve in these connections which will vary the pressure in the chamber 26 according to changes in boiler conditions. I have illustrated, for the sake of simplicity, a valve which is actuated in response to change in boiler water level.

Leading from the chamber 20 is a conduit 21 which communicates with a chamber 22 in a three way valve which I am pleased to term pilot valve 40. Also communicating with the chamber 22 is a conduit 23 which leads to the feed water line at a point 24 between the feed water valve and the boiler. The valve 40 is provided with two seats 25 and 26 screwed into the valve casing and has a closure member 2'7 which may be lowered onto the seat 25 to close communication through the conduit 23 or which may be raised into contact with the seat 26 to close communication with a chamber 28 and open communication through the conduit The chamber 28 communicates with a conduit 29 leading to the feed water line as at 30, between the valve 10 and the feed water pump, wherein fluid pressures are carried in substantial excess of boiler pressure.

The closure member 2'7 of the valve 40 is carried by a stem 41 which extends through a stufiing box 42 and engages at its upper end a diaphragm,

not shown, which closes a diaphragm chamber 43. An adjustable spring 44 exerts an upward pressure on the valve stem opposing fluid pressures established in the chamber 43. Thus the spring 44 may be adjusted to raise the closure member 2'7 onto the seat 26 and hold the closure member on that seat until the pressure in the chamber 43 exceeds any given amount. While the closure member is thus held, the chamber 20 communicates with the conduit 23 and the feed water line at the point 24 so that what we may term boiler pressure is maintained in the chamber 20. When the pressure in the chamber 43 exceeds the pressure exerted by the spring 44, the closure member 27 is forced downwardly toward the seat 25 so that communication is established between the point 30 in the feed water line and the chamber 20 of the valve 10 via the conduit 29, the chambers 28 and 22 and the conduit 21.

in the course of movement of the closure member 27, there will be a period when the member 2'7 is removed from both of the seats 25 and 26 so that pressures which are greater than boiler pressure but less than pump pressure, are established in the chamber 20. These pressures will depend, other things being equal, on the proportion of the openings afforded on one hand between the seat 25 and the closure member and. on the other hand between the seat 26 and the closure member. Thus if the closure member 27 is very close to the seat 26 and remote from the seat 25, the pressure in the chamber 20 will exceed boiler pressure by only a small amount. On the other hand, when the closure member 2'7 is very close to the seat 25 and remote from the seat 26, the pressure in the chamber 20 will be only a small amount less than that exerted by the feed water pump, or more accurately, that pressure established at the point 30 in the feed water line. By screwing the seats 25 and 26 toward or away from each other the total permissible movement of the closure member 27 may be decreased or increased, and the pressure variation in the chamber 20 effected by a given movement of the closure 2'7 correspondingly adjusted. Since the movement of the closure 2'7 is proportional to the pressure variation in the diaphragm chamber 43, assuming a constant force to be exerted by the spring 44, the relation of increments of change of pressure in the diaphragm chamber 43 to the resulting increments of change of pressure in the chamber 20 can be varied as desired.

To actuate the valve 40, I provide a conduit 45 leading to a pressure generator 46 which is carried on a conduit 4'7 and may be entirely similar to the generator '7, but preferably it is disposed at a different elevation and inclined at a different angle. The elevation and angle of the generator 46 with relation to the generator '7, is a matter of design which may be determined by the problem encountered in each specific installation. As shown, the pressure generator 46 is somewhat lower than the pressure generator '7 and its inclination to the vertical is less than the inclination of the pressure generator 7. By this arrangement of parts the generator '7 is first acted upon when the water level in the boiler falls and the feed valve 3 is opened. Upon a further decrease in the water level in the boiler, the pressure generator 46 is acted upon to exert its influence upon the diaphragm 43.

In the conduit 45, I place a hand valve 50land in the conduit 6, a hand valve 51, and I provide an interconnecting conduit 52 having a hand valve 53. In this manner, if I desire, I may establish equal pressures in the chambers 5 and 43 using both generators in common or I may use the generators independently to take advantage of their different relative positions. It will be appreciated that while I have illustrated a pressure connection for the valve 40 leading to a device responsive to change in boiler water level, that various other conditions might readily be used to create or reduce this actuating pressure.

In operation presume that the boiler is steaming under a given load, that the water level lies along the plane of the line L; that the pressure in the chamber 5 is sufiicient to hold the feed Water valve in the position shown, that the pressure in the chamber 43 is not suflicient to move the closure member 27 away from the seat 26 so that boiler pressure is established in the chamber 20. Under this condition, the fluid pressure drop across the feed water valve equals the pressure in the spring 16 which may, for example, be fifty pounds. Variations from this condition within any desired limits may effect only the opening of the feed water valve but variations within any limits, which are determined by the compression in the spring 44 or the arrangement and connections from the generators '7 and 46, may effect both the opening of the feed water valve and the pressure established in the chamber 20. Thus if an increase in load causes a drop in water level which sets up a pressure in the chamber 43 great enough to move the closure member 27 away from the seat 26; then while the feed water valve is being opened, the pressure in the chamber 20 of the valve 10 is being increased. The downward pressure on the stem 13 of the valve 10 is then increased so that the pressure drop is increased across the feed water valve and may in a given instance rise from to '75 or 100 or more pounds so that the flow of feed water is not only increased by reason of the increased opening of the feed water valve but is also increased by reason of the greater pressure drop established across it. If the drop in water level be great, then the feed water valve may be thrown wide open and the movement of the valve 40 may establish pump pressure in the chamber 20 to throw the valve 10 wide open so that a maximum flow of feed water is obtained to rehabilitate the water level.

From the foregoing, it will appear that I have provided a device for controlling the fluid pressure drop across a given orifice by varying the actuating pressures exerted on the difierential valve, that more specifically I have provided a device for controlling the fluid pressure drop across a boiler feed Water valve by directing either drum pressure or pump pressure or a resultant of the two on the diaphragm of the differential valve.

While I have illustrated and described a preferred form of my invention and a particular embodiment thereof, I do not care to be limited in this or any manner other than by the claims appended hereto.

I claim:

1. In a boiler feed pipe, the combination of an orifice, a fluid actuated valve disposed adjacent thereto and controlling the pressure drop across said orifice, means for conducting actuating fluid to said valve from a point between said orifice and the boiler, means for conducting actuating fluid to said valve from the feed water pipe ahead of said valve, and valve means responsive to changes in boiler water level associated with both said last named means for controlling the flow of fluid therethrough.

2. The combination of a boiler, a feed water pipe, an orifice in said pipe, a feed water pump, a diaphragm actuated valve positioned between the orifice and the pump, means for establishing fluid pressure on one side of said diaphragm equal to the pressure between said valve and said orifice, a conduit for conducting fluid to the opposite side of said diaphragm from a point between said orifice and said boiler, a conduit for conducting fluid to said last mentioned side of said diaphragm from a point between said valve and said pump, valve means responsive to changes in boiler water level associated with both said conduits for controlling the flow of fluid therethrough and to vary the pressure exerted upon the diaphragm.

3. The combination of a boiler, a feed water pipe, an orifice in said pipe, a feed water pump, a diaphragm actuated pressure controlling valve disposed between said pump and said orifice,- means connecting one side of said diaphragm with the feed water" line between said valve and said orifice, a conduit connecting the opposite side of said diaphragm with the feed line betweenthe boiler and said orifice, a conduit connecting said last mentioned side of said diaphragm with the feed line between the pump and said valve,- and valve means responsive to changes in boiler conditions associated with said conduits for con-' trolling the flow of fluid therethrough and for varying the pressure exerted on said diaphragm, whereby the pressure on said diaphragm may be increased in amounts exceeding the boiler pressure.

4. In a boiler feed system, the combination of a feed water pipe, a feed Water valve in said pipe, a fluid actuated differential valve in said pipe for controlling the pressure drop across the feed water valve, said fluid actuated valve having a diaphragm upon opposite sides of which fluid pressures are established for moving the valve, the pressure on one side being equal to the pres sure ahead of the feed water valve and urging the differential valve to closed position, the pressure on the opposite side of the diaphragm being normally taken from the low pressure side of the feed water valve, fluid conducting meansleading from the last named side of said diaphragm to the low pressure side of the feed water valve and to a point in the feed water line ahead of both of said valves, and means responsive to boiler conditions for controlling the flow through said fluid conducting means for varying the pressures on said last named side of said diaphragm.

5. A device for controlling fluid pressure drop across a boiler feed water valve comprising a differential valve positioned in the feed water line ahead of the feed water valve and having a diaphragm chamber, conduits leading from said chamber to points of fluid pressure substantially equal to boiler pressure and pump pressure respectively, a three-way valve controlling the flow through said conduits, and means responsive to water level in the boiler for actuating said valve.

6. A device for controlling the fluid pressure drop across an orifice such as a boiler feed water valve comprising a differential valve having a diaphragm actuated in response to the diiTerence in fluid pressures imposed upon opposite sides of said diaphragm, the lower side of said diaphragm communicating with the high pressure side of the feed water valve, the upper sidev of said diaphragm having one connection with. the low pressure side of the feed water valve and having another connection leading to the feed water line ahead of both of said valves, a threeway valve controlling said connections and means responsive to boiler conditions for actuating said three-way valve whereby pressures exceeding by various amounts the pressure on the low side of the feed water valve are established in said chamber in response to changes in boiler conditions.

7-. The combination of afeed water pipe, a

boiler, a feed water valve actuated in response to changes in the water level in the boiler and means for controlling the fluid pressure drop across said feed water valve comprising a fluid actuated valve having a diaphragm chamber and a connection leading from said chamber to the low pressure side of the feed water valve, a second connection from said diaphragm chamber leading to a source of pressure higher than the boiler pressure and means responsive to changes in coiler water level for closing one of said connections while opening the other to vary the pressure in said chamber.

8. A boiler feed system comprising in combination, a boiler, a feed water pump, a feed water pipe, a feed water valve in said pipe, a device responsive to opposed fluid pressures for controlling the pressure drop across the feed water valve, means associated with said device for varying one of the pressures to which said device is responsive whereby the fluid pressure drop across the feed water valve is varied, and means responsive to change in boiler water level for actuating said last named means to vary the opening of the feed Water valve.

9. In a boiler feed pipe, the combination of a fluid actuated valve, fluid conducting means extending to said'valve from a point between the same and the boiler, fluid conducting means extending to said valve from a point ahead or" said valve, and valve means responsive to changes in boiler conditions associated with both said last named means for controlling the flow of fluid therethrough.

10. In a boiler feed pipe, the combination of a fluid actuated valve having a part subjected to opposed fluid pressures for moving it, means for establishing the fluid pressure of the outlet side of said valve on one side of said part, means for conducting actuating fluid to the other side of said part from the inlet side of said valve, means for conducting actuating fluid to said valve from a point between said valve and the boiler, and valve means responsive to changes in boiler water level associated with both said last named means for controlling the flow of fluid therethrough.

11. In a boiler feed pipe the combination of a fluid actuated valve having a part subjected to opposed fluid pressures for moving it, means for establishing the fluid pressure of the outlet side of said valve on one side of said. part, means for conducting actuating fluid to the other side of said part from the inlet side of said valve, and valve means responsive to changes in boiler conditions associated with said last named means for controlling the passage of fluid through said last named means.

12. In a boiler feed pipe, the combination of a fluid actuated valve having a part subjected to opposed fluid pressures for moving it, means for establishing valve outlet pressures on one side of said part, means for conducting fluid from said pipe to other side of said part, and means responsive to changes in boiler conditions associated with said last named means for controlling the flow of fluid therethrough.

13. In a boiler feed pipe, the combination of an orifice, a fluid actuated valve disposed adjacent thereto and responsive to changes in pressure drop through said orifice, a spring associated with said valve means and exerting a force to move it, means for conducting actuating fluid to said valve from a point between said orifice and the boiler, means for conducting actuating fluid to said valve from the feed water pipe ahead of said valve, and valve means responsive to changes in boiler conditions associated with both said last named means for controlling the flow of fluid therethrough.

14. A feed water regulating apparatus comprising in combination a boiler, a feed water pipe, a pressure actuated feed water valve in said pipe, pressure generator means connected to said feed water valve and associated with the boiler responsive to changes in boiler conditions and adapted to generate varying pressures for moving said valve, differential valve means in said feed water pipe ahead of said feed water valve for controlling the pressure drop across said feed water valve, a relatively sensitive pilot valve for controlling said differential valve and thereby regulating the pressure drop across said feed water valve, and a fluid connection between said generator and said pilot valve, said pilot valve responding to changes in pressure more rapidly than said feed water valve whereby the pressure drop across said feed water valve is varied before said feed water valve moves in a manner to compensate for the delay in movement of said feed water valve.

15. In combination with a boiler, a feed water pipe associated therewith, a valve in said pipe for varying the flow of feed water therethrough, said valve having a part adapted to be subjected to fluid pressure for moving the same, and means responsive to changes in boiler conditions for admitting actuating fluid to said part, said means including a pilot valve and a separate valve closure member forming a part of a second valve movable between a pair of opposed seats, said seats being adjustable toward or away from each other to vary the sensitivity of said means.

16. In a boiler feed water regulating system, a three way pilot valve adapted to control the flow of actuating fluid to a fluid actuated valve in response to changes in boiler conditions, said pilot valve including a passage to be connected to said fluid actuated valve, and passages adapted to be connected to sources of fluid at relatively high and relatively low pressures, valve seats separating said first named passage from the other of said passages, and a valve closure member operable between said seats, the latter being adjustable toward or away from each other.

1'1. In a boiler feed system, a boiler, a feed water pipe, an orifice in said pipe, and means for controlling the fluid pressure drop across said orifice comprising a fluid pressure actuated valve having a part subjected on opposite sides to different fluid pressures whereby the differential there between serves to actuate said valve, and means responsive to changes in boiler conditions for varying said differential pressure.

18. In a boiler feed water system, a boiler, a feed water pipe, an orifice in said pipe, means for controlling the fluid pressure drop across said orifice, said means comprising a fluid pressure actuated valve having a part subjected on one side to the pressure existing on one side of said orifice and subjected on the other side to a pressure differing therefrom in an amount which is controlled by the magnitude of said pressure drop whereby the resultant differential on said part serves to actuate said valve, and means responsive to changes in boiler conditions for varying the said diiferential pressure.

19. In a boiler feed water system, a boiler, a pump, a feed water pipe therebetween, an orifice in said pipe, means for controlling the fluid pressure drop across said orifice comprising a fluid pressure actuated valve having a part subjected on one side to the pressure existing on one side of said orifice and subjected on the other side to the pressure existing on the other side of said orifice, whereby a differential pressure is created on said part for actuating said valve, means exerting a relatively constant force in opposition to said differential pressure whereby changes in said differential pressure actuate said valve, and means responsive to changes in boiler conditions for varying said differential pressure.

20. In a boiler feed system, a feed water valve, a diaphragm actuated valve in which fiuid pressure is established on one side of the diaphragm equal to pressure between said valves, in combination with conduits leading to the opposite side of said diaphragm from sources of pressure substantially equal to pump pressure and boiler pressure respectively, pressure actuated valve means in said conduits and means responsive to changes in boiler conditions for exerting pressure on said valve means for increasing the opening in one conduit while decreasing the opening in the other.

21. In a boiler feed system, a feed water valve, a diaphragm actuated valve in which fluid pressure is established on one side of the diaphragm equal to pressure between said valves, in combination with conduits leading to the opposite side of said diaphragm from sources of pressure substantially equal to pump pressure and boiler pressure respectively, valve means in said conduits, said valve means including a valve seat in each of said conduits, and a common closure member for said valve seats, and means for actuating said closure member simultaneously to increase the opening in one conduit and decrease the opening in the other.

22. In a boiler feed system, a feed water valve, a diaphragm actuated valve having a diaphragm chamber in which fluid pressure is established on one side of the diaphragm equal to pressure between said valves, in combination with conduits leading to the opposite side of said dia-- phragm from sources of pressure substantially equal to pump pressure and boiler pressure respectively, a three-way valve responsive to changes in boiler conditions and connected to said conduits and to said diaphragm chamber having a single closure member movable to iacilitate communication between said chamber and one conduit while restricting communication with the other conduit.

23. In a boiler feed system, a feed Water valve, a diaphragm actuated valve having a diaphragm chamber in which fluid pressure is established on one side of the diaphragm equal to pressure between said valves, in combination with conduits leading to the other side of said diaphragm from sources of pressure substantially equal to pump pressure and boiler pressure respectively, a threeway valve connected to said conduits and to said diaphragm chamber and operable in response to changes in boiler conditions to facilitate communication with one conduit while restricting communication with the other.

24. In a boiler feed system, a feed water valve, a diaphragm actuated valve in which fluid pressure is established on one side of the diaphragm equal to pressure between said valves in combination with a three-way valve, a conduit leading from said valve to the opposite side of said diaphragm, two other conduits leading to said three-way valve, one from a source of pressure equal substantially to boiler pressure and the other from a source of pressure equal substantially to pump pressure, said three-way valve having a closure member and an adjustable spring for holding said closure member in a position to close communication with the source of pressure substantially equal to pump pressure, and means actuable in response to changes in boiler conditions acting against said spring to move said closure member.

25. In a boiler feed system, a feed water valve,

a pressure actuated valve having opposed pressure chambers in which fluid pressure is established in one chamber equal to pressure between said valves, in combination with a three-way valve, a conduit leading from said valve to the opposite chamber, two other conduits leading to said three-way valve, one from a source of pressure equal substantially to boiler pressure and the other from a source of pressure equal substantially to pump pressure, said three-way valve having a closure member and an adjustable spring for holding said closure member in a position to close communication with the source of pressure substantially equal to pump pressure and means actuable in response to changes in boiler conditions acting against said spring to move said closure member.

26. In a boiler feed system, a boiler, a feed water pipe, an orifice in said pipe, and means for controlling the fluid pressure drop across said orifice comprising a fluid pressure actuated valve having a part subjected on one side to fluid pressure between said valve and said orifice and on the other side to fluid pressure on the other side of said orifice whereby the difierential betweeen said pressures serves to actuate said valve, and

means responsive to changes in boiler conditions for controlling said diiierential pressures.

HENRY J. MASTENBROOK. 

